The complexity and cost of local access networks can be significantly decreased by using the dual capability of semiconductor light sources to both emit and detect light. Based on this property, a very simple full-duplex communication system can be realized with a single fiber connected at both ends to a single optical device, which operates as a transceiver, transmitting and photodetecting alternatively, in the so called "ping-pong" mode. A local access network based on this principle has been recently reported by T. Kurosaki, et al, "Dynamic Properties of 1.3 .mu.m Semi-insulating BH Light-Emission-and-Detection (LEAD)-diode for Subscriber TCM Transmission Systems", Elec. Letters, vol. 31, February 1995, pp. 189-191. That system uses a laser transmitter in a Time-Division Multiplex (TDM) arrangement with a star coupler to multiplex a plurality of links together in the same fiber. Undesirably, because of the multiplexing technique used, each link must be modulated at a relatively high bit rate to transmit signals in assigned time slots and consequently the power budget and required receiver sensitivity must be increased accordingly. In addition, TDM imposes very stringent synchronization requirements between the upstream links. What is needed is a simple local access network based on the "ping-pong" mode having none of the above problems.